This invention relates to a sintered glass body which has an opaquely mottled pattern and presents the appearance of a natural rock and, hence, is useful as a decorative building material. The opaqueness is attributed to an oxide powder dispersed in the sintered glass body.
There are some kinds of glass or semi-glass bodies with decorative patterns. For example, JP 55-29018 shows glass-ceramics articles with a marble-like pattern produced by integrating small granules of a glass from which needle-like crystals can be precipitated and heating the integrated granules at a temperature suited to crystallization. However, this technique is not convenient for industrial applications firstly because the type of the crystallizable glass is strictly limited and also because the crystallizing heat treatment requires a very high temperature and strict control of the heating and cooling conditions.
JP-A 60-151251 shows, as a synthetic rock, a foam glass body having a large number of island-like regions scattered in a finely foamed glass matrix which is different in color from the island-like regions. The island-like regions too have fine pores and hence exhibit a light diffusing effect. The foam glass body is produced by firing a mixture of a glass powder containing a pigment and a granulated glass material of the island-like regions. However, in a foam glass of this type it is inevitable that open pores exist in the surfaces as a cause of stains by depositon of dust and susceptibility to scratches. Besides, glass bodies high in porosity are often insufficient in flexural and compressive strengths.